Liquid flowing device

ABSTRACT

A liquid flowing device includes: a plate-like vibration body; and a driving section that vibrates the vibration body in a thickness direction, wherein at least a portion of an end section of the vibration body in an in-plane direction continuously becomes thinner toward an end of the vibration body.

BACKGROUND

1. Technical Field

The present invention relates to liquid flowing devices for flowing liquid.

2. Related Art

As devices for flowing liquid, screw propellers for ships and various types of pumps are available. Also, fish fins may be considered as devices for flowing liquid. Such device mechanisms use particular shapes and movements specifically selected to effectively flow liquid. In recent years, it has become necessary to achieve a further improvement in the efficiency of liquid flowing devices and a further size reduction thereof depending on their usage.

The structure and principle of fish fins may be applied to pumps. For example, Japanese Laid-open Patent Application JP-A-5-272497 describes a pump for flowing liquid by reciprocally rotationally driving a fin about a rotary shaft within a specified angle range. The document describes that the pump can be formed with smaller and fewer components.

However, in the case of a pump driven by a mechanism with a rotary shaft, bearings for supporting the rotary shaft, sealing for sealing liquid and the like are required. Such sealing may also pose an obstruction to size-reduction of pumps. Similarly, pumps using a screw propeller mechanism need sealing devices for sealing liquid, and thus have a limitation in size-reduction. Also, for example, the screw propeller mechanism has a drawback in that its efficiency considerably deteriorates when its rotation speed is increased in order to increase the fluid flow rate.

SUMMARY

In accordance with an advantage of some aspects of the invention, it is possible to provide a liquid flowing device with a novel mechanism for flowing liquid.

In accordance with an embodiment of the invention, a liquid flowing device includes: a plate-like vibration body; and a driving section that vibrates the vibration body in a thickness direction, wherein at least a portion of an end section of the vibration body in an in-plane direction continuously becomes thinner toward an end of the vibration body.

The liquid flowing device set forth above can flow liquid.

In the liquid flowing device in accordance with an aspect of the invention, the driving section may vibrate the vibration body by flexing the vibration body.

In the liquid flowing device in accordance with an aspect of the invention, the driving section may vibrate the vibration body in a manner to move the position of the vibration body in its entirety in parallel.

In the liquid flowing device in accordance with an aspect of the invention, at least the thinner portion of the vibration body may be submerged in liquid, and the liquid may be flowed with a speed component in an in-plane direction of the vibration body and in a direction in which the vibration body becomes thinner.

In the liquid flowing device in accordance with an aspect of the invention, the driving section may have a piezoelectric element.

In the liquid flowing device in accordance with an aspect of the invention, the driving section may have a solenoid.

In the liquid flowing device in accordance with an aspect of the invention, the vibration body vibrates with a frequency that may be a resonance frequency of the vibration body, or a resonance frequency of an entire body including the vibration body and the driving section.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic plan view of a liquid flowing device 100 in accordance with an embodiment of the invention.

FIG. 2 is a schematic cross-sectional view of the liquid flowing device 100 in accordance with the embodiment of the invention.

FIG. 3 is a schematic perspective view of a driving section 20 in accordance with an embodiment of the invention.

FIG. 4 is a schematic perspective view of a driving section 20 in accordance with an embodiment of the invention.

FIGS. 5A, 5B and 5C are schematic diagrams of operations of the driving section 20 in accordance with the present embodiment.

FIG. 6 is a schematic diagram of operations of the driving section 20 in accordance with the present embodiment.

FIG. 7 is a schematic diagram of operations of the driving section 20 in accordance with the present embodiment.

FIG. 8 is a schematic cross-sectional view of a liquid flowing device 200 in accordance with an embodiment of the invention.

FIG. 9 is a schematic plan view of the liquid flowing device 200 in accordance with the embodiment of the invention.

FIG. 10 is a schematic side view of a liquid flowing device 300 in accordance with a modified example.

FIG. 11 is a schematic plan view of a liquid flowing device 400 in accordance with a modified example.

FIG. 12 is a schematic cross-sectional view of the liquid flowing device 400 in accordance with a modified example.

FIG. 13 is a schematic cross-sectional view of a liquid flowing device 500 in accordance with a modified example.

FIG. 14 is a schematic perspective view of a vibration body 20 a in accordance with a modified example.

FIG. 15 is a schematic perspective view of a vibration body 20 b in accordance with a modified example.

FIG. 16 is a schematic perspective view of a vibration body 20 c in accordance with a modified example.

FIG. 17 is a schematic perspective view of a vibration body 20 d in accordance with a modified example.

FIG. 18 is a schematic cross-sectional view of the vibration body 20 d in accordance with the modified example.

FIG. 19 is a schematic perspective view of a vibration body 20 e in accordance with a modified example.

FIG. 20 is a schematic side view showing operations of a liquid flowing device 600 in accordance with a modified example.

FIG. 21 is a schematic side view showing operations of a liquid flowing device 700 in accordance with a modified example.

FIG. 22 is a schematic plan view showing operations of a liquid flowing device 800 in accordance with a modified example.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

A preferred embodiment of the invention is described below with reference to the accompanying drawings. It is noted that the embodiment described below explains an example of the invention.

1. Liquid Flowing Device

An example of a liquid flowing device 100 in accordance with an embodiment of the invention is described with reference to the accompanying drawings. FIG. 1 is a schematic plan view of the liquid flowing device 100 in accordance with the present embodiment. FIG. 2 is a schematic cross-sectional view of the liquid flowing device 100 in accordance with the embodiment of the invention. A cross section taken along a line A-A of FIG. 1 corresponds to FIG. 2. FIG. 3 and FIG. 4 are schematic perspective views of examples of driving sections 20 in accordance with the embodiment, respectively.

The liquid flowing device 100 has a driving section 10 and a vibration body 20.

The driving section 10 includes piezoelectric layers 14 a and 14 b with a base member 12 interposed therebetween, and electrodes 16 a and 16 b provided further outside on the piezoelectric layers, as shown in FIGS. 1 and 2. The driving section 10 thus includes two piezoelectric elements formed up and down on the base member 310 as being the center thereof.

The base member 12 is a base substrate of the driving section 10, and is a member for retrieving mechanical outputs of the driving section 10 to outside. The base member 12 has a circular disk shape in the illustrated example, and a portion thereof protrudes more outwardly than the piezoelectric layers 14 a and 14 b such that it can be connected to other members. The base member 12 can be deformed by the piezoelectric layers 14 a and 14 b. The base member 12, upon its deformation, can drive other members connected thereto. The base member 12 is capable of extension and contraction deformation in its lengthwise direction shown in the figure (a direction along a line A-A) and of flexural deformation in in-plane and out-of-plane of the base member 12. In the present embodiment, the case where the base member 12 undergoes extension and contraction deformation is described. The base member 12 may be made of any material, and is formed from a material having conductivity, in the illustrated example. For this reason, the base member 12 serves as one of a pair of electrodes for applying an electric filed to the piezoelectric layers 14 a and 14 b. Also, in the illustrated example, the base member 12 is structured as a common electrode for the piezoelectric layers 14 a and 14 b provided up and down thereof When the base member 12 is formed from a material without conductivity, a conductive layer or the like may be provided on the base member 12 above and below thereof for applying an electric field to the piezoelectric layers 14 a and 14 b.

The piezoelectric layers 14 a and 14 b are provided above and below the base member 12. The piezoelectric layers 14 a and 14 b expand and contract, respectively, upon application of an electric field to each of them. The base member 12 deforms by expansion and contraction of the piezoelectric layers 14 a and 14 b. The direction of expansion and contraction of each of the piezoelectric layers 14 a and 14 b can be arbitrarily designed by changing the polarity of application voltage and the directions in which the piezoelectric layers 14 a and 14 b are polarized. In the example shown in FIG. 1 and FIG. 2, the polarization direction of the upper and lower piezoelectric layers 14 a and 14 b and the direction of electric field to be applied to the upper and lower electrodes 16 a and 16 b are composed such that the piezoelectric layers 14 a and 14 b can expand and contract in a direction in their lengthwise direction (the direction along the line A-A). It is noted that the base member 12 can be flexed in an out-of-plane direction by changing the polarization direction and the direction of electric field. The piezoelectric layers 14 a and 14 b may be formed from piezoelectric material, such as, for example, lead zirconate titanate (Pb(Zr, Ti)O₃), lead zirconate titanate niobate (Pb(Zr, Ti, Nb)O₃) or the like.

The electrodes 16 a and 16 b are provided on the piezoelectric layers 14 a and 14 b, respectively, on the outer sides with respect to the base member 12. Each of the electrodes 16 a and 16 b is one of the pair of electrodes that apply an electric field to each of the piezoelectric layers 14 a and 14 b. The electrodes 16 a and 16 b supply electric power to cause expansion and contraction in the base member 12. The electrodes 16 a and 16 b are formed from a conductive material.

The vibration body 20 is provided near the tip portion of the base member 12 of the driving section 10, as shown in FIG. 1 and FIG. 2. The vibration body 20 has a plate-like configuration. In accordance with the present embodiment, the direction of deformation of the driving section 10 is a lengthwise direction (a direction along the line A-A in the figure) of the driving section 10 (base member 12). The vibration body 20 can continuously expand and contract, and vibrate in a vibration direction B (indicated by an arrow in the figure). The vibration body 20 is provided such that the thickness direction of the vibration body 20 is aligned with the lengthwise direction (the vibration direction B) of the driving section 10. In other words, the vibration body 20 is provided in a manner to have a movement component in its thickness direction. The vibration body 20 is affixed to the base member 12 of the driving section 10 in the illustrated example. The vibration body 20 and the base member 12 may be bonded together through another member such as a jig, as long as the movement of the driving section 10 can be transmitted to the vibration body 20.

As shown in FIG. 3, an end section 22 (outside of an imaginary line L in the figure) of the plate-like vibration body 20, when viewed in the thickness direction (indicated by a sign X in the figure), has at least a portion (an end section 24 in the figure) that becomes continuously thinner toward an end E1. The vibration body 20 has a sloped surface T1 inclined at an angle φ and a sloped surface T2 inclined at an angle ψ with respect to a plane (shaded with dots in the figure) orthogonal to the thickness direction X. Also, as shown in FIG. 4, the plane orthogonal to the thickness direction X (hatched (in a manner similar to the above) in the figure) may concur with the sloped surface T2 (ψ=0°).

In the present embodiment, the thickness direction of a plate-like object means a direction along a shortest side of a rectangular box that contains the plate-like object and has a smallest volume. However, when a plate-like object does not have a sloped surface inclined with respect to a plane perpendicular to a thickness direction of a rectangular box, the thickness direction is a direction along the second shortest side of the rectangular box.

2. Operation of Liquid Flowing Device

FIGS. 5A, 5B and 5C are schematic cross-sectional views showing actions of a liquid flowing device in accordance with an embodiment of the invention. FIGS. 5A, 5B and 5C show states of the sloped surface T1 and the sloped surface T2 of the vibration body 20 in motion while being submerged in liquid. FIGS. 5A and 5B show states of the vibration body 20 when it is moved in a direction indicated by an arrow in solid line, respectively. FIG. 5C shows a state of the vibration body 20 when it is reciprocally vibrated in directions indicated by a two-direction arrow in solid line. Arrows in broken line in FIGS. 5A-5C schematically indicate the flow of liquid.

As shown in FIG. 5A, when the vibration body 20 moves in a direction indicated by an arrow, the liquid present on the side of the sloped surface T2 is pushed by the sloped surface T2, and generates a flow along the sloped surface T2 (see an arrow in broken line on the left side). On the other hand, at the same time, the liquid present on the side of the sloped surface T1 is pulled by the sloped surface T1, and generates a flow along the sloped surface T1. However, as the liquid on the side of the sloped surface T1 is pulled by the sloped surface T1, the flow has large disturbances such that the flow speed of the liquid on the side of the sloped surface T1 (see an arrow in broken line on the right side) becomes smaller than the flow speed of the liquid on the side of the sloped surface T2. Accordingly, a liquid flow to be generated around the vibration body 20 equals to the sum of the flows of the liquid present on the side of the sloped surface T2 and on the side of the sloped surface T1, whereby the flow of the liquid is generated in a direction in which the vibration body 20 becomes thinner. Similarly, as shown in FIG. 5B, when the vibration body 20 moves in an opposite direction with respect to the direction shown in FIG. 5A, a flow of the liquid is generated around the vibration body 20 in a direction in which the vibration body 20 becomes thinner.

The vibration body 20 shown in FIG. 5C reciprocally vibrates in directions indicated by a two-direction arrow in solid line. Therefore a flow of the fluid to be generated around the vibration body 20 equals to the sum of flows of the liquid indicated by a total of four arrows in broken line in FIG. 5A and FIG. 5B. Accordingly, when the vibration body 20 vibrates in its thickness direction, the fluid around the vibration body 20 flows in a direction in which the vibration body 20 becomes thinner.

The vibration body 20, which can generate a liquid flow indicated in FIG. 5C when the vibration body 20 is vibrated in its thickness direction, has the following configuration. (1) At least a portion of the end section 22 of the vibration body 20 in an in-plane direction becomes thinner toward the end; and (2) the vibration body 20 has at least one sloped surface inclined with respect to a plane perpendicular to the vibration direction. Furthermore, the sloped surface may not be limited to a flat surface, and may be a curved surface.

FIG. 6 and FIG. 7 are schematic diagrams for describing the relation between the configuration of the driving section 20 and the vibration direction. The direction in which the vibration body 20 is vibrated by the driving section 10 only needs to be a direction having a component in the thickness direction of the vibration body 20. For example, as shown in FIG. 6, even when the vibration direction is inclined at an angle θ with respect to the thickness direction, the liquid flows according to the sum of flows (indicated by arrows in broken lines) generated around the vibration body 20. As a result, a flow can be generated in a direction in which the vibration body 20 becomes thinner. This effect can be generated even when the angle θ is greater than the angle φ, as indicated in the figure. Also, by selecting the vibration direction such that liquid flows are generated in the same direction (i.e., θ≦φ or θ≦ψ) when the vibration body 20 is reciprocated, the efficiency in flowing the liquid becomes better. Furthermore, as shown in FIG. 7, when the vibration direction and the thickness direction of the vibration body 20 are in consonance with each other (θ=0°), the liquid flow can be generated more effectively.

The liquid flowing device 100 in its entirety or the vibration body 20 has a resonance frequency, respectively. When the vibration described above is close to the resonance frequency, the energy loss becomes smaller, and the flow of the liquid can be more effectively generated. Also, the frequency with which the vibration body 20 is vibrated can be freely set. The frequency of vibration can be optimized, taking into account the configuration and size of the vibration body 20 and the liquid flowing device 100, and the property of the liquid. For example, the frequency of vibration with which the vibration body 20 is vibrated may be 20 kHz through 1 MHz.

3. Method for Manufacturing Liquid Flowing Device

A liquid flowing device 100 in accordance with a present embodiment of the invention may be manufactured as follows. A driving section 10 and a vibration body 20 may be manufactured independently from one another, and then assembled together, whereby the liquid flowing device 100 can be manufactured.

A method for manufacturing the driving section 10 may include the steps of forming piezoelectric layers 14 a and 14 b on a base member 12, and forming electrodes 16 a and 16 b on the outer sides of the piezoelectric layers 14 a and 14 b. The step of forming the piezoelectric layers 14 a and 14 b on the base member 12 may be conducted by, for example, a sol-gel method or a CVD (Chemical Vapor Deposition) method or the like. The step of forming the electrodes 16 a and 16 b may be conducted by a sputter method, a vapor deposition method or the like. Also, a polarization treatment to the piezoelectric layers 14 a and 14 b may be conducted by applying an electric field to the base member 12 and the electrodes 16 a and 16 b. The vibration body 20 may be manufactured by, for example, processing a metal plate. The driving section 10 and the vibration body 20 thus manufactured may be bonded together by, for example, welding, adhesion, fixing with a jig such as screws.

4. Modified Example

A variety of modifications can be implemented in the liquid flowing device in accordance with the present embodiment as follows.

4.1. Modification of Driving Section

FIG. 8 is a schematic cross-sectional view of a liquid flowing device 200 in accordance with a modified example. FIG. 9 is a schematic plan view of the liquid flowing device 200. A cross section taken along a line A-A in FIG. 9 corresponds to FIG. 8.

FIG. 8 and FIG. 9 schematically show the liquid flowing device 200 in which its driving section 10 is formed with a solenoid 30. The solenoid 30 includes an iron core 32 and a coil 34. Upon application of a current to the coil 34, the iron core 32 slides in a direction along the line A-A in the figure in response to the current. When the current applied to the coil 34 is an alternate current, the iron core 32 has vibration motions along a vibration direction B. A vibration body 20 may be appropriately affixed to the iron core 32, as shown in FIG. 9. The liquid flowing device 200 is capable of flowing liquid when the vibration body 20 is vibrated in its thickness direction, like the embodiment described above.

FIG. 10 is a schematic cross-sectional view of a liquid flowing device 300 in accordance with another modified example. The liquid flowing device 300 has a driving section 10 that is formed with piezoelectric elements, and a base member 12 that is capable of flexurally vibrating in its thickness direction. The piezoelectric elements are generally the same as the piezoelectric elements of the liquid flowing device 100 except that the piezoelectric layers 14 a and 14 b and the electrodes 16 a and 16 b are divided from each other, respectively. The liquid flowing device 300 has a vibration body 20 provided above the base member 12 through a jig 11, as shown in FIG. 10. The vibration body 20 becomes thinner toward its end in an in-plane direction in an upward direction as viewed from the base member 12. When the driving section 10 is flexurally vibrated in its thickness direction, the center section of the driving section 10 at which the vibration body 20 is connected inclines, as schematically shown by broken lines p in the figure. In this manner, the vibration body 20 can vibrate as indicated by arrows in the figure. In this case, it is noted that the vibration body 20 displaces with its base section as a center, but does not have a rotation axis. By the liquid flowing device 300 having the driving section 10 modified in the manner described above, the vibration body 20 is vibrated in its thickness direction, like the embodiment described above, whereby liquid can be flowed.

FIG. 11 is a schematic plan view of a liquid flowing device 400 in accordance with another modified example. FIG. 12 is a schematic cross-sectional view of the liquid flowing device 400. A cross section taken along a line C-C of FIG. 11 corresponds to FIG. 12.

The vibration direction B of the driving section 10 of the liquid flowing device 400 is different from that of the liquid flowing devices 100 and 200 described above. Also, in the liquid flowing device 400, the direction in which an end section in an in-plane direction of the vibration body 20 becomes thinner toward its end is different from that of the liquid flowing devices 100 and 200. The direction in which the driving section 10 of the liquid flowing device 400 vibrates the vibration body 20 is in a thickness direction of the base member 12. In the present example, the vibration body 20 is integrally continuous with the base member 12. The driving section 10 of the liquid flowing device 400 has the same structure as that of the driving section 10 of the liquid flowing device 100. In the liquid flowing device 400, polarization directions of the piezoelectric layers 14 a and 14 b of the driving section 10, or electric fields to be applied thereto are different from those of the liquid flowing devices 100 and 200, and deformation of the base member 12 takes place in an out-of-plane direction of the base member 12. In the liquid flowing device 400, the vibration body 20 is also vibrated in its thickness direction. Accordingly, when the liquid flowing device 400 is operated while the vibration body 20 is submerged in liquid, a flow of the liquid can be generated in a direction in which the vibration body 20 becomes thinner, like the liquid flowing devices 100 and 200.

FIG. 13 is a schematic cross-sectional view of a liquid flowing device 500 in accordance with another modified example. The liquid flowing device 500 is generally the same as the liquid flowing device 400 except that the direction in which its vibration body 20 becomes thinner is different from that of the liquid flowing device 400. Also, the vibration body 20 of the liquid flowing device 500 becomes thinner in a direction going away from the driving section 10. In the liquid flowing device 500, the vibration body 20 is also vibrated in its thickness direction. Accordingly, when the liquid flowing device 500 is operated while the vibration body 20 is submerged in liquid, a flow of the liquid can be generated in a direction in which the vibration body 20 becomes thinner, like the liquid flowing devices 100 through 400. Moreover, in the liquid flowing device 500, when the vibration body 20 is vibrated along a vibration direction B, the vibration body 20 flexes itself. In this manner, the self flexural vibration of the vibration body 20 can also generate a flow of the liquid in a direction in which the vibration body 20 becomes thinner.

In accordance with the present embodiment, as described above, many modifications can be made to the driving section 10. The driving section 10 is not limited in any respects, as long as it can vibrate the vibration body 20 in its thickness direction. The mechanism, configuration and vibration direction of the driving section 10 may be appropriately selected according to the usage of the liquid flowing device.

4.2. Modification of Vibration Body

FIGS. 14 through 17 are schematic perspective views of vibration bodies in accordance with modified examples. A two-direction arrow in solid line in the figures indicates a vibration direction B.

A vibration body 20 a shown in FIG. 14 has surfaces that are in parallel with a plane orthogonal to a thickness direction. Even when the vibration body 20 a is modified in this manner, at least a portion (i.e., an end section 24) of an end section 22 (an area outside an imaginary line L in the figure) in an in-plane direction becomes thinner toward its end. Therefore, vibration of the vibration body 20 in the thickness direction can generate a liquid flow in a direction in which the vibration body 20 becomes thinner.

A vibration body 20 b shown in FIG. 15 has surfaces that are in parallel with a plane orthogonal to a thickness direction, and has a portion 26 that extends in a depth direction in the figure, like a handle (a portion shown in broken line). In the vibration body 20 b, the driving section 10 can be connected to the handle section 26, such that the degree of freedom in disposing each member of a liquid flowing device can be made higher. Also, with the vibration body 20 b, the handle section 26 can be used as a base member 12 of the driving section 10, whereby the vibration body and the base member can be formed in one piece, like the liquid flowing device 400 exemplified in FIG. 11.

A vibration body 20 c shown in FIG. 16 has a single surface that is inclined with respect to a plane orthogonal to a thickness direction. Even when the vibration body 20 c has a single inclined surface, a portion (an end section 24) of an end section 22 in an in-plane direction becomes thinner toward an end, whereby a liquid flow can be generated in a direction in which the vibration body 20 c becomes thinner, when vibrated in the thickness direction. Also, the vibration body 20 in accordance with an aspect of the embodiment can be in an asymmetrical configuration on the front and back sides thereof, like the vibration body 20 c.

A vibration body 20 d shown in FIG. 17 has four sloped surfaces (slopes T1 through T4) inclined with respect to a plane orthogonal to a thickness direction, and has two directions in which an end section 24 in an in-plane direction becomes thinner toward an end. FIG. 18 is a cross section at a plane shaded with dots in the vibration body 20 d shown in FIG. 17. In FIG. 18, flows of liquid generated when the vibration body 20 d is vibrated in its thickness direction are schematically indicated by arrows in broken line. When a vibration body has a configuration that becomes thinner in a plurality of directions, like the vibration body 20 d, flows of liquid can be generated in these directions, respectively, when the vibration body is vibrated in its thickness direction.

FIG. 19 is a schematic perspective view of a vibration body 20 e in accordance with a further modified example. The vibration body 20 e shown in FIG. 19 has a surface inclined with respect to a plane orthogonal to the thickness direction, and the inclined surface is in a curved surface. Even when the vibration body 20 e is modified in this manner, a portion of the end section in an in-plane direction becomes thinner toward the end. Therefore, a flow of liquid can be generated in a direction in which the vibration body 20 e becomes thinner, when vibrated in its thickness direction. Also, the direction in which the vibration body 20 e becomes thinner can be freely selected by changing its configuration, as shown in FIG. 19.

In the present embodiment, many modifications can be made to the vibration body 20, as described above. The vibration body 20 is not limited to any configuration as long as at least a portion of the end section 22 in an in-plane direction becomes thinner toward the end. The configuration and vibration direction of the vibration body 20 can be appropriately selected depending on the usage of the liquid flowing device.

4.3. Modification of Vibration Mode

FIG. 20 is a schematic cross-sectional view of a liquid flowing device 600 capable of flexurally vibrating its base member 12 in its thickness direction, with its vibration body 20 being submerged in liquid. A boundary s in the figure may represent a wall of a container, a tube and the like, or a surface of liquid. The vibration body 20 of the liquid flowing device 600 is submerged in liquid. Broken lines t and u in the figure schematically show deformation states of the liquid flowing device 600 when it is vibrated. Also, an arrow indicated by a mark B in FIG. 20 indicates a vibration direction.

As shown in FIG. 20, in the liquid flowing device 600, the vibration body 20 can be vibrated in its thickness direction by the driving section 10. This vibration can be modulated in a plurality of modes by the control of the driving section 10 as indicated by broken lines in the figure. Examples of vibration modes are indicated by broken lines t and u. Referring to the broken line t, the base member 12 displaces at the position of the boundary s. When the liquid flowing device 600 has a displacement at such a position of the boundary s, liquid can be flowed. When the boundary S is a tube wall, a diaphragm that allows the base member 12 to penetrate the tube wall and allows vibration of the base member 12 may be provided. Referring to the broken line u, a node of vibration of the liquid flowing device 600 is present near the boundary s. The liquid flowing device 600 can be operated such that a node of vibration is generated near the boundary S. As a result, a simpler diaphragm that allows the base member 12 to penetrate the tube wall and allows smaller vibration may be provided. By this, the reliability of the liquid flowing device 600 can be improved.

FIG. 21 is a schematic cross-sectional view showing a liquid flowing device 700 capable of vibrating its base member 12 by extension and contraction, with its vibration body 20 being submerged in liquid. A boundary s in the figure may represent a wall of a container, a tube and the like, or a surface of liquid. The vibration body 20 of the liquid flowing device 700 is submerged in liquid. In the figure, broken lines v schematically show an example of vibration mode of the liquid flowing device 700 when it vibrates by extension and contraction. Positions of the liquid flowing device 700 along its lengthwise direction are taken along a horizontal direction in the figure, and displacements of the liquid flowing device 700 corresponding to the positions are taken along a vertical direction in the figure. Also, an arrow indicated by a mark B in FIG. 20 indicates a vibration direction.

As shown in FIG. 21, the vibration body 20 in the liquid flowing device 700 can be vibrated in its thickness direction by the driving section 10. The vibration can be obtained by controlling the driving section 10, like the liquid flowing device 100. Referring to the broken lines v, a node of vibration of the liquid flowing device 700 is present near the boundary s. The liquid flowing device 700 can be operated such that a node of vibration is generated near the boundary s, like the liquid flowing device 600 described above. As a result, a simpler diaphragm that allows the base member 12 to penetrate the tube wall and allows smaller vibration may be provided. However, even when the liquid flowing device 700 has a displacement at the position of the boundary s, liquid can be flowed by using an appropriate diaphragm, like the liquid flowing device 600 described above.

FIG. 22 is a schematic plan view showing a liquid flowing device 800 capable of vibrating its base member 12 by extension and contraction, with its vibration body 20 being submerged in liquid. A boundary s in the figure may represent a wall of a container, a tube and the like, or a surface of liquid. The vibration body 20 of the liquid flowing device 800 is submerged in liquid. In the figure, broken lines w schematically show an example of vibration mode of the liquid flowing device 800 when it vibrates by extension and contraction. Positions of the liquid flowing device 800 along its lengthwise direction are taken along a horizontal direction in the figure, and displacements of the liquid flowing device 800 corresponding to the positions are taken along a vertical direction in the figure. Also, an arrow indicated by a mark B in FIG. 22 indicates a vibration direction, which is a depth direction with respect to a paper surface in the figure.

As shown in FIG. 22, the vibration body 20 in the liquid flowing device 800 can be vibrated in its thickness direction by the driving section 10. The vibration can be obtained by appropriately controlling the driving section 10. Referring to the broken lines w, a node of vibration of the liquid flowing device 800 is present near the boundary s. The liquid flowing device 800 can be operated such that a node of vibration is generated near the boundary s, like the liquid flowing device 600 described above. As a result, a simpler diaphragm that allows the base member 12 to penetrate the tube wall and allows vibration of the base member 12 may be provided. Also, even when the liquid flowing device 800 has a displacement at the position of the boundary s, liquid can be flowed by using an appropriate diaphragm that can allow such a displacement.

The embodiments of the invention are described above However, a person skilled in the art should readily understand that many modifications can be made without departing in substance from the novel matter and effects of the invention. Accordingly, all of such modified examples are also deemed to be included in the scope of the invention. 

1. A liquid flowing device comprising: a plate-like vibration body; and a driving section that vibrates the vibration body in a thickness direction, wherein at least a portion of an end section of the vibration body in an in-plane direction continuously becomes thinner toward an end of the vibration body.
 2. A liquid flowing device according to claim 1, wherein the driving section flexes the vibration body to vibrate.
 3. A liquid flowing device according to claim 1, wherein the driving section vibrates the vibration body to move the position of the vibration body in its entirety in parallel.
 4. A liquid flowing device according to claim 1, wherein at least the thinner portion of the vibration body is submerged in liquid, and the liquid flows with a speed component in an in-plane direction of the vibration body and in a direction in which the vibration body becomes thinner.
 5. A liquid flowing device according to claim 4, wherein the driving section has a piezoelectric element.
 6. A liquid flowing device according to claim 1, wherein the driving section has a solenoid.
 7. A liquid flowing device according to claim 1, wherein the vibration body vibrates with a frequency that is one of a resonance frequency of the vibration body and a resonance frequency of an entire body including the vibration body and the driving section. 